Leviticus 18:13

Thou shalt not uncover the nakedness of thy mother's sister, &c.] Which is the same relation as before, an aunt by the mother's side; wherefore, if such a marriage was unlawful, this must also, and for the same reason: for she [is] thy mother's near kinswoman; the same phraseology is used here as in the preceding verse; (See Gill on Leviticus 18:12); and by the same rule a woman might not marry her uncle, whether by father or mother's side, the relation being the same, and this reaches to great-uncle and great-aunt; instances of women marrying their uncles, and men their aunts, among the Heathens, have been given, as among the Persians and Lacedaemonians by Herodotus F12, and among the Romans by Tacitus F13, but were, in his time, new things with the latter.